ASM Phase II Real Time Dispatch and Reserve Constraint Penalty Factors rev2.0 NEPOOL Markets...

ASM Phase IIReal Time Dispatch and Reserve Constraint Penalty Factors rev2.0

NEPOOL Markets CommitteeJune 28/29, 2005Jim MilliganISO-NE Markets Development

Presentation Title

© 2005 ISO New England Inc. 2

Outline

• Review activities that take place prior to real time

– System and locational Reserve Requirements

– Resource commitment in DA and RAA

• Overview of real time dispatch

• Proposed Reserve Constraint Penalty Factors

• Use of RCPFs

– Dispatch Solutions

• Reserve Shortages

Presentation Title


System Reserve Requirements

• System Reserve Reserve requirements are for real time– Provide resources to protect power system from supply loss– NERC/NPCC/ISO Procedures dictate:

• Ten Minute Reserves to cover 1st Contingency supply loss

• Thirty Minute Reserves to cover ½ 2nd Contingency supply loss

– NEPOOL/ISO Procedures allow Ten Minute Reserves to be met with combination of Spinning and non-Spinning Reserves (nominally 50% of each)

– Unless otherwise constrained, all eligible resources can be used to meet System Reserve requirements

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Locational Reserve Requirements

• Locational Reserves are required to protect sub-areas of the power system from local generation or transmission 2nd contingencies in order to restore 1st contingency protection

• Based on system status– Transmission system including planned or forced outages– Generation availability including economic operation

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Energy and Reserve Procurements

• Preliminary Reliability Assessment– Daily analysis by Transmission Group of expected power system

conditions for next Operating Day based on initial and forecasted conditions

• Status of transmission system (planned and forced outages)

• Expected generation operation (initial status, planned and forced outages, forecasted operation)

• ISO Load Forecast

– Evaluation includes forecast of both system and locational capacity and reserve requirements

– Results are inputs to DAM clearing process

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Energy and Reserve Procurements (cont)

• Portfolio Obligations from LFRM are converted to physical resources in conjunction with DA Offers

• System reserve requirements are inputs to DAM clearing as capacity constraints and DAM provides an accounting of eligible resources to meet requirements

• DAM clears based on inputs and produces hourly energy schedules for resources

• Results are posted and are inputs to RAA process

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• Updated Reliability Assessment– Based on:

• DAM clearing

• Updated availabilities from Re-Offer Period

• Updated system conditions, including Load Forecast

– The Transmission Group updates the assumptions and assessment of system requirements for the Operating Day

– This updated assessment of requirements is input to the RAA process

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• Resource Adequacy Assessment– RAA outputs

• If RAA does not detect any violations of requirements, no additional resource commitments are required

• If RAA detects violations, commitments may be required:– If system capacity/reserves or 1st contingency coverage, next economic

resource(s) to satisfy constraints are notified of possible commitment (startup instructions issued)

– If 2nd contingency coverage to meet local constraints, next economic resource(s) to satisfy constraints are notified of commitment (startup instructions issued)

• RAA process results in a viable Real Time Operating Plan to meet all requirements for the Operating Day based on information available at time of execution

Presentation Title


Real Time Dispatch

• Objective of real time dispatch algorithm is to determine the least costly means of serving the next increment of load and reserves at each node in the system from available resources given all identified constraints

• Identified constraints include;– Active transmission constraints– Resource operating constraints including ramp rates and limits– System reserve requirements (new with ASM)– Locational reserve requirements (new with ASM)– Real time energy (load) requirements– Regulation requirements

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Real Time Dispatch (cont)

• Available Resources– On-line dispatchable Resources (Generators and Asset Related

Demand)– On-line non-dispatchable Generators and scheduled External

transactions (energy requirements)– Off-line Fast Start Generators

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• Real Time ex-ante dispatch inputs– Power system state from State Estimator

• Generator MW outputs

• Actual Load at each node

• Calculated flows and limits for each branch element

• Defined interface limits and actual flows

• Active transmission constraints

– Next period load forecast from EMS load forecast algorithm– System and locational reserve requirements from EMS Reserve

applications– Resource Bid/Offer data

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• Real time ex-ante dispatch outputs– Desired Dispatch Points (MW) and reserve designations for all

dispatchable resources to meet the energy, reserve and transmission constraints

– Ex-ante dispatch rates (energy LMP) for all pricing nodes and reserve clearing prices for each reserve product for system and reserve zones

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• If all allocations and assignments from LFRM, DAM clearing and RAA are reasonable accurate, real time dispatch throughout the Operating Day has the set of Resources to meet the energy and system/locational reserve requirements for the next real time dispatch cycle

• Therefore, under normal conditions, the real time dispatch produces nodal energy LMPs based on an economic dispatch, including transmission constraints, of available Resources and reserve clearing prices of zero.

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• Non-normal dispatch conditions– Re-dispatch to meet system TMSR reserve requirements

• When re-dispatch is required to maintain the system TMSR reserve requirement, the resource(s) re-dispatched will incur an opportunity cost to provide the reserves

• When this condition occurs, the real time TMSR Reserve Clearing Price will be the highest opportunity cost of the resource dispatched to provide the reserves

• All resources that are designated as providing TMSR will be eligible to receive the TMSR Clearing Price for the MWs of reserve provided

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• Non-normal dispatch conditions– Re-dispatch to meet local reserve requirements

• See example

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• Non-normal dispatch conditions– System Capacity Deficiency (OP#4)

• Capacity deficiencies exist when there is insufficient resources available in real time to meet the energy and reserve requirements of the power system

• Capacity deficiencies can result from a) peak load conditions or real time loads substantially higher than forecast or b) forced outage(s) in R/T and the lack of available resources after the outage(s) to meet the requirements

Presentation Title



• Non-normal dispatch conditions– System Capacity Deficiency (OP#4)

• If there is insufficient capacity in real time to meet the energy and reserve requirements, the energy needs of the system will be met and the reserve requirements will not be met

• Under these conditions, one or more reserve constraint violation(s) will occur and non-zero real time reserve clearing price(s) will be produced by the Reserve Constraint Penalty Factor(s)(RCPF)

• The RCPFs have been developed to recognize the value of the reserve shortage and reduced reliability state of the power system

Presentation Title


Proposed Reserve Constraint Penalty Factors

Location

Product RoS Reserve Zones

TMSRS $50 n/a

TMNSRS $850 n/a

TMORS $100 n/a

TMORL n/a $50

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Derivation of RCPFs

• RCPFs have been established to be consistent with operational requirements and practices of power system.

• RCPFs reflect the costs the ISO would be willing to incur to procure reserves given the $1000/MW Energy Cap.

• RCPFs will replace the existing Reserve Shortage Condition Pricing Rule as defined in Market Rule 1.

• RCPFs will provide mechanism to reflect reserve shortages in stages for system and locational requirements.

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Use of RCPFs

• RCPFs have two functional uses under ASM Phase II:

– Allows the real time dispatch algorithm to achieve a feasible solution when a Reserve Constraint cannot be satisfied,

– Determines a real time Reserve Clearing Price (by product and location) when a Reserve Constraint cannot be satisfied.

Presentation Title


Dispatch Feasibility

• The real time dispatch algorithm will include system reserve requirements for TMSR, TMNSR and TMOR and local reserve requirements for TMOR for each Reserve Zone

• The real time reserve requirements (system and locational) will be calculated based on real time conditions and will be inputs to the dispatch

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Dispatch Feasibility (cont)

• Additional Dispatch Rules:

– Unused MWs of higher quality reserves will be available to meet lower quality reserve requirements

– Lower quality Reserve Clearing Prices will cascade upward to higher quality Reserve Clearing Prices

• Reserve capability of on-line Resources will be computed based on either 10*MRR or 30*MRR from DDP constrained by EcoMax using MRR at DDP.

• Reserve capability of off-line Resources will be computed based on CLAIM10/30 Offer data constrained by EcoMax.

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• Objective function of real time dispatch will be to minimize the cost of meeting all constraints from available Resources.

• Constraints include:

– Nodal/system energy balance,

– Resource specific constraints (limits, MRR, etc.)

– Transmission constraints (branch, interface, etc.)

– System/local reserve requirements

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• RCPFs will be set equal to values as specified.• When a reserve constraint cannot be satisfied with

available resources, the constraint will be violated in the dispatch solution, and the RCPF will act “conceptually” as a reserve resource with infinite MW and a price equal to the RCPF.

• This “concept” will allow the dispatch algorithm to arrive at a feasible solution.

Presentation Title


Locational Example of RCPFs

• Initial conditions:Actual EcoMin EcoMax Energy MRR

Reserve

– GenA 25 25 100 $70 1 30– GenB 80 50 100 $50 5 20– GenC 0 5 25 $150 C10=25 25– GenD 0 5 25 $200 C30=25 25

GenA and GenB committed, Local Reserve Req’t = 100 MW

Interface Limit =200MW, Interface Flow=150MW

Local Load = 255

System LMP = $50, Reserve Prices = $0

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Conditions at t=0

Local Load = 255

GenA 25 R=30

GenB 80 R=20

GenC 0 R=25

GenD 0 R=25

Load 255

L Res = 150

Local LMP $50

L RCP = $0

Limit = 200

Actual = 150

System LMP = $50

System RCPs = $0

System

Reserve Zone

Presentation Title


Conditions at t=1

Local Load = 300

GenA 25 R=30

GenB 100 R=0

GenC 0 R=25

GenD 0 R=25

Load = 300

L Res = 105

Local LMP = $55

L RCP = $0

Limit = 200

Actual = 175

System LMP = $55

System RCPs = $0

System

Reserve Zone

Energy Balance is satisfied

Local Reserve Req’t is satisfied

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Conditions at t=2

Local Load = 310

GenA 30 R=30

GenB 100 R=0

GenC 0 R=25

GenD 0 R=25

Load = 310

L Res = 100

Local LMP = $70

L RCP = $15

Limit = 200

Actual = 180

System LMP = $55

System RCPs = $0

System


Local Reserve Req’t is satisfied

Re-dispatch of Interface – similar to Gen opportunity cost

Reserve Zone

Presentation Title


Conditions at t=3

Local Load = 351

GenA 70 R=30

GenB 100 R=0

GenC 0 R=25

GenD 0 R=25

Load = 351

L Res = 99

Local LMP = $105

L RCP = $50

Limit = 200

Actual = 181

System LMP = $55

System RCPs = $0

System


Local Reserve Req’t is violated

Reserve Zone

Presentation Title


Conditions at t=4

Local Load = 371

GenA 71 R=29

GenB 100 R=0

GenC 0 R=25

GenD 0 R=25

Load = 371

L Res = 79

Local LMP = $120

L RCP = $50

Limit = 200

Actual = 200

System LMP = $55

System RCPs = $0

System


Local Reserve Req’t is violated

Reserve Zone

Presentation Title


Reserve Shortages

• Previous example shows local reserve shortage and use of local RCPF

• Similar concept employed for system reserve shortages• Typical condition would begin with a shortage of TMOR

followed by shortage of TMNSR, and in extreme cases, a shortage of TMSR.

• Under this scenario, system TMOR RCPF would be violated first followed by system TMNSR RCPF and finally system TMSR RCPF

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Reserve Shortages (cont)

• Frequency of System Reserve Shortages– Reference: Analysis of Historical Reserve Shortages White

Paper

• Historical analysis indicates that the Control Area has experienced a deficiency in Operating Reserves (TMOR) in real time approximately 0.26% of time.

• Of the total Number of deficient conditions (24), five resulted in a deficiency of TMNSR, and of the five, three may have resulted in a deficiency of TMSR.

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Reserve Shortages (cont)

• Historical information does not exist to perform similar analysis of locational reserve shortage conditions. The ISO is continuing to investigate the feasibility of producing such an analysis.

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Discussion and Questions

ASM Phase II Real Time Dispatch and Reserve Constraint Penalty Factors rev2.0 NEPOOL Markets...

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